What is the main problem in No More Dead Dogs and how was it solved?

Wallace is presented as an honest boy whose lack of diplomacy gets him into trouble. Although honesty itself is not a problem, his lack of social filters that protect him from the effects of his honesty create difficulties for him. While the author does not advocate hypocrisy, he suggests that evaluating the possible effects of one’s behavior and seeking help from others offer a more prudent course of action.
When Wallace honestly expresses his opinion of a book assigned in school, his teacher harshly punishes him. This teacher is opposed to open intellectual debate and instead is determined to impose his personal opinions on his students. Although this punitive behavior is clearly wrong, his authority put Wallace in a difficult situation. Wallace ultimately learns that direct confrontation can be futile: finding an answer requires not only individual creativity but also openness and trust in others, whose perspective can help provide an unanticipated solution—such as letting the dog (in the play) live.

No More Dead Dogs, written by Gordon Korman, is a novel for younger readers focused on a boy in middle school named Wallace Wallace (that's right, first and last name). Because his touchdown won his school football team the championship, he has recently become popular with other students.
Problems start off in the book when Wallace, who doesn't like to lie, writes a book report truthfully saying how much he hated the book Old Shep, My Pal. His teacher, Mr. Fogelman, gives him detention until he writes new report, and he requires Wallace to go to rehearsals of the drama club for detention. This keeps Wallace from going to football practice, and he eventually realizes that he'd rather be in drama club than on the football team.
While there are other things going on in the plot, I would say the main problem in No More Dead Dogs is that someone is trying to sabotage the school play, and Wallace is being blamed for it. Wallace has been making friends in rehearsals and making suggestions to change the show, but he is banished from the play when he is suspected for the vandalism. This problem is eventually solved when Rachel realizes that her brother Dylan, who was upset that Wallace left the football team, was responsible for the sabotage. Everything works out, and Rachel and Wallace decide to go on a date.